Process of recovering metals from ores.



No. 702,582. Patented lune l7; I902. J. w. mam. & J. H. BURFEIND.

PROCESS OF REGOVERING METALS FROM OBES.

(Application filed. Feb. 6, 1901.) (No Model.) 2 Sheets-Sheet I.

12 a I L \\\\\Q\\\\\ "Wm y I @Qflnessea nveniors JamesWN ll a I JoachimH..Buvfeim1 No. 702,582. Patented lune l7, I902.

J. W. NEILL &. J. H. BUBFEIND. PROCESS OF RECOVERING METALS FROM ORES.

(Application filed Feb. 6, 1901.)

2 Sheets-Sheet 2.

(No Model.)

' nvenior James Neill yjacl'dm Burfina 'Wifnesses:

@w. W of XM@ UNITED: "STATEs PATENT O F JAMES W. NEILL AND JOAOHIM H.BURFEIND, OF SALT LAKE CITY, UTAH.

PROCESS OF RECOVERING METALS FROM: ORl-IS.

SPECIFICATION forming part of Letters Patent Np. 702,582, dated June 17,1902.

' application filed February 6, 1901. $erial No. 46,172- (No specimens.)I

T0 at whom it may concern:

Be it known that we, JAMES W. NEILL and J OACHIM H. BURFEIND, citizensof the United States, and residents of Salt Lake City, in the county ofSalt Lake and State of Utah, have invented a certain new and usefulProcess of Recovering Metals from "Ores, of which the following is aspecification.

Our invention relates,"generally speaking, to thosemetallurgicaloperations wherein a mass of pulp in a suitableliquid-containing tank or receptacle is subjected to the action of anydesired chemical agent or reagent for the purpose ofchanging itschemical constitutionas, for instance, in those processes of recoveringmetals from their ores wherein a solvent is used to dissolve out themetal by a leaching action.

Our invention is more particularly designed for use in those operationswherein a stream or streams of gas under pressure are employed toagitate the pulp, said gas being formed in whole or'in part of the agentor reagent useful in the dissolving, treating, oxidizing, or otherchemical processes to be performed, although in some cases the gas mightbe one which would be inert, in which case the solution or mixture wouldembody all of the chemical agents active in the process, and the gaswould merely serve as a substitute for the mechanical rotating stirringapparatus heretofore employed in the receptacle containing the crushedore commingled with the L proper liquid.

One of the useful applications of our invention is .in the process ofextracting copper from copper ores by the use of sulfurousacid gas, asdescribedin-United States Letters Patent granted to James W. Neill May29, 1900, No. 650,784, although, as will be readily understood by thoseskilled in the art, the invention might be used with other ores or otheragents, the nature of the agent being adapted in each case to the natureof the orebracing any mixture of material and liquid adapted to form thesemifluid mass which can be readily agitated and. circulated by the action of gas under pressure".

Our invention consists,substantially, inagitating the charge of orecontained in the receptacle by means of a stream or streams of gasforced into the same to keep the pulp in a constant state of agitationand to secure a complete exposure of tlie'materia'l to the action of thechemical agents used in the process, recovering in any way the metalfrom the solution after the action-has been carried on to the properpoint and returning the gas or gases released by the recoveringprocessfor use in agitating fresh charges of ore.

In carrying out this invention itis obvious that the particular way ofrecovering the metal from the solution isimma terial, though we preferto employ, particularly when the process is applied to the 're'covery'ofcopper from its ores, a precipitation process in which theliquid-bearing solution is obtained by filtration of the pulp andisheated to drive 0d the gas used as the agent in the preliminaryoperation.

Inapplying our process to the process of the prior patent referred tothe gas used would originally consist, preferably, in whole or in partof sulfurous-acid gas. As will be hereinafter described, however, it isdesirable to use a gas obtained either from the burning of pyrites ornative sulfur, in which case from three'to five per cent. of the gaswould naturally be sulfurous-acidgas. In this case the remaining "olumeof' the gases serves the mechanical function of keeping the pulp in thetank in a state of agitation for the purpose already described and forother purposes to 'be hereinafter'mentioned.

Another part of our invention consists in subjecting the ore tosuccessive operations in a series or range of tanks or vatsth'roughwhich the gas used in the treatment of the ore is forced in succession,the" series begin niug with that one of "the vatsinwhich the.

eral plan of the same in outline, showing the plant extended to embody anumber of ranges or series of construction of the gas-outlet of the pipewhich delivers the gas into the tank.

We will first describe in general the construction of the tank in whichthe operation is to be conducted. The form of this tankis immaterial;but it is preferably made round, and its bottom is conical and slopes atan angle of forty-five degrees, more or less, to the center, at whichpoint a discharge-openingis provided. In the drawings the several tanksare indicated by the numeral 5. Assuming that the ore is subjected tothree successive operations, three such tanks are employed, and the pulpis delivered from one tank to the other in any suitable wayas, forinstance, by gravity, which is the method shown in the drawings, wherethe tanks are represented as arranged at different levelsand thedelivery-pipe (marked 12) passes the pulp from the bottom of one tank tothe next lower tank. The tanks are covered at the top, preferably, so asto permit the gas used in the lower tank to be collected in the topthereof and passed therefrom by a pipe 13 to the next tank of theseries. The tank is built either of wood or of iron and the iron eitherlined with wood or with lead or with other material or merely paintedwith some proper acid or solution resisting paint, according tocircumstances. The connections 13 may be made by rubber hose attached toproper nippies. Entering the tank, preferably at the top, is agas-delivery pipe 14, the outlet 15 of which is arranged near the apexof the conical bottom, as shown, so as to deliver a stream or streams ofthe gas employed at said point and to thereby secure an agitation of thepulp from the bottom and produce the action hereinafter described. It ispreferable to construct this part of the apparatus so that it shalldeliver the gas downwardly, since in this way we avoid in a largemeasure the danger of clogging resulting from shutting down, theair-supply, and which would be liable to occur if the opening werearranged to deliver the gas or air upwardly.

The gas-outlet may consist of a cup in the center of which a hole ofsmall diameter is bored and with a numberof otherholes around the edgeto give egress to the gas in small streams, so that the gas will enterthe tank broken up and in better condition to be absorbed. The hole inthe bottom of the outlet throws a stream of gas into thedischargeopening and keeps this clear of sand, while the other holesaround the edge throw their stream of gas against the sloping sides ofthe tank and keep the entire contents thereof in a constant whirl, thestream of pulp rising in themiddledescendingalong theoutside,where itfalls on the sloping sides only again to meet the stream of gas. Theform of this outlet, however, may be obviously very much Varied. At eachdelivery-outlet a suitable controlling cook or valve 16 is employed.

The gas supplied to the pipe 14 is furnished under pressure by anysuitable means. Said pipe may enter in any other way; but it ispreferable to arrange it as shown, since it thereby affords littleobstruction to the movement of the pulp or to the exit thereof from thetank.

At the top of the drawings is indicated at 2a an ore-hopper, above whichis a narrowgage track 3, which leads to the ore-bin, said hopper beingadapted to receive the ore which has been first crushed to the necessarydegree of fineness. From the car the ore is dumped into the hopper andfrom this passed into the leaching-tank, which has been previouslycharged with water containing some sulfurous acid, two tons of waterbeing preferably used to one ton of the ore. This water may beobtainedfrom the last washing of previous charges and from the tower 25,which maybe placed at the end of the stream to absorb the last traces ofthe S0 gases or to collect gases obtained in any other way.

Other parts of the apparatus shown and employed in the process will bementioned in connection with the operation, which will be described ascarried on in connection with a copper ore to be leached in the tank bysulfurous acid.

In carrying out the leaching operation the top tank (No. 1leaching-tank) is first filled with water or with the leaching fluid,according to circumstances. The gas or air which has been passed fromthe air-compressor 6, suitably located on one of the lower platforms, iskept continuously passing in series through the tanks, passing firstfrom the top downward through the pipe in No. 3 leaching-tank, where itescapes through the hole in the bottom of said pipe, and owing to thepressure at which it is forced into this tank it agitates the contentsof the tank, including the leaching solution or water in which theore-pulp is contained. The gas or air escapes from the solution at thetop of the No. 3 tank, passes similarly through the escape-pipe fromthis tank into the centrally-located stirring-pipe of the secondleach-tank, where it again stirs the solution or ore-pulp. It is againreleased, passes through the pipe, and again through thecentrally-located pipe into No. 1 leachingtank, where it again acts as astirring agent. The gas or air passes from this No. 1 tank either intothe open air, or in cases where the gas may be the reagent to be used inthe solution of the metals of the ore-pulp, and therefore any waste fromthe escape of this gas must be avoided, this gas is passed from the No.l leach-tank into and through a suitable wooden or other tower 25, whereit is met by a stream of descending water and the gas absorbed, to beused again in the process. It will be seen, therefore, that the one com.pressor forcing the gas through the various connecting-pipes, in at thebottom and out of the top of each succeeding tank, stirs all the be dugout, with attendant loss of time andmanual labor. By our improved methodif the compressor stops and the sands settle to to the bottom of theconical tank no such harm is done. So soon as the gas is again forcedthrough the central stirring-pipe it penetrates through'the sand andimmediately commences to bubble through and gradually forces the entirematter again into suspension,

as it was before the interruption. In carrying out the leaching ortreating operation we preferably operatetwo' or more tanks, preferablysituated,as shown, one above the other, so that the solution and pulpfrom'the upper may flow by gravity into the next lower tank, and wepreferably perform the leaching or treating operation in successivestages, finishing the operation inthe lowest tank, (marked No. 31eaching-tank,) Where if the gas used in the operation contains theleaching agent-for instance, sulfurous acid-this gas isin its strongestcondition, and therefore in best condition to completely dissolveall themetals or materials to be extracted from the ore pulp. The escaping gas.from the lowest tank passing through each of the other tankssuccessively is successively reduced in'its strength, and thus theaforesaid gas or other agent is used in the most economical mannerpossible. Should the gas contain no solvent, but be merely air, it isstill of use as an oxidizing agent as Well as a stirring agent, which'inmany leachingmethods is desirable, economical, and'ofgreat commercialadvantage. So soon as small sample extract by simple methods from' thelowest tank shows the 'pulp contained in this tank to be barren of'thematerial to be extracted then this lowest tank may be emptied by openingthe Valve in the discharge connection, and the pulp and solution flowsat once into suitable settlingvats or into pressure-tanks 7, from whichit and suitable or as more fully hereinaftersetforth. So soon as thelowest leach-tank is emptied its discharge-valve is closed and thedischarge-valve of No. 2 tank thereupon. opened. This permits thedischa'rge'of the.

contents of the No. 2 tank into the N o. 3 tank, and so soon as No. 2is'emptied No. 1 tank is similarly discharged into No. 2 tank, whereuponNo. 1 tank jsfpromptly charged with a fresh amount ofwater or dilutedsolution, as may be desirable, and the crushed ore thereupon introducedfrom the ore-hopper.

Thus the ore to beleached is successively treated in each tank, and thetime of leaching and stirring is thus to be multiplied by the number oftanks and thelength'of time in each tank.' Thus if an ore'has to'be allowed to remainin the No. 3 tank aperiod of three hours'and there arethree tanksin-the.

unit-the ore willbe subjected to a total stir ring agitation andexposure to theinfluence of the stirring-gas for a period of nine hours.The pressure at which the gas must be delivered through thestirring-pipe into the lowest leach-tank must necessarily be sufficientto overcome hydrostatic pressure of the columnsof Water containedin theseveral tanks composing the unit. Thus if there are three tanks inthe'unit and each tank con tains water or solution to the depth of ten feet,or a total of vfifty feet hydrostatic pressure, the gas will have to beforced 'into'the first tank ata pressure approximating fifteen pounds tothe square inch, and the lowest .tank must be able to-withstand suchpressure. The next or No. 2 tank will-only be subjected to a hydrostaticpressure of twenty feet or approximately ten pounds and the No. 1 tankcorrespondingly approximately five pounds. I

The advantages which we claim for this lot) system are therefore First.A much cheaper installation, as the tanks do not have to beequipped withmechanical rotating stirring apparatus, and-thenec- 'ess'ary shafting,belting, and pulleys to drive the same are done'away with.

Second. Freedom from disastrous stoppages caused by slight cessation ofthe stirring mechanism.

Third. Morecomplete agitation,and the'reforemore complete ex'posure ofthe material to be leached to the action of the solution or gas, orboth.

' Fourth. Successive exposure in successive chargesto the solvent actionof gas of successively-increasing strength. This isan im portant featureof our process as applied.

either to the recovery'of copper or of other metal from its ore. Where,as'is usual, the

gangue or pulp treated containsingredients I some of which are easilysoluble or susceptible to the action of the reagent employed,-

but others are not so easily soluble, the latter'will'remain longer inthe'gangue or pulp andwill requirefor their: recovery either a long timein a weak solution or solvent-0r a short time-only with a strongsolvent. By our improvedloperation the more refractory parts of the oreor pulp only aresubjectedto a longer 'action', but are finally exposedto the action of the strongest solution. This improved operation enablesus to treat ores in a very much shorter time than is usually required.

Fifth. Extremely simple mechanical handling and delivery of materialswithout manual labor.

In completing the operation of extracting the copper the liquid obtainedfrom the titerpresses may be carried to the precititationtanks 30,(indicated in plan in Fig. 2,) where the liquid is heated in an ysuitable way known in the art, and the excess of SO gases released inthese heating-tanks may be carried to the tower 25 to be there absorbedby the water,or be carried directly to the compressor which delivers itat once again into the tanks containing the ore charges. Ordinarily itwill be preferable to deliver the released gas direct to the compressor,as it is released in the heating-tanks, practically speaking, as pure SOgas mixed, perhaps, with a little steam, and this pure gas enriches thegas coming from the burners or roastingfurnaces to such an extent thatits action is much more rapid, and whereby a great deal of time issaved.

As already stated, we may obtain the S0 gas from the roasting of theore. In that case we draw the gas from the sulfur-burners or theroasting-furnaces through water in a washer for the purpose of freeingit from any impurities, cooling, and condensing it. If the gas isobtained from roasting-furnaces or blast-furnaces, the flue-dust andvolatilized metals will also be effectually regained in the washer.After the gas is thus washed,condensed, and cooled it is taken by thecompressor and forced into the ore charge, and at the point where thecompressor takes the washer gas we also conduct the released gas fromthe heating-tank, which, as stated, being nearly pure S0 enriches thegas from the burners or furnaces, which is entirely novel and new and ofgreat importance, as already mentioned. The stronger the gas the lesstime will be required to dissolve the copper or other metals soluble inthat menstrum. Thus when using a strong gas the ore to be treated may bea great deal coarser than it should be if only a weak gas can be had.

32 is a drying-floor adapted to receive the copper precipitates obtainedfrom the tanks 30, and 33 indicates tanks to be employed for theclean-up of the solution.

34: indicates in plan a furnace which may be used in any of the finaloperations.

In the plan we show three series of leaching-tanks, all adapted toreceive their ore from the same track and the final tank of each seriesconnected by waste gas pipe 40 with the tower 25.

The compressors which would be employed in the process are indicated inoutline at 41,

and the pipe which brings the S0 gas from the wash-tanks to thecompressors is indicated by the numeral 42.

What we claim as our invention is- 1. The herein -'described improvementin leaching copper ores, consisting in forcing sulfurous-acid gasthrough a charge of pulp to agitate the same mechanically and therebyassist in the leaching action, separating the solution from theore,recovering the metal from such solution, thereby releasing the gasand returning the gas released by such operation for use in agitatingand dissolving the metal from fresh charges of ore.

2. The herein-described improvement in leaching copper ores consistingin forcing sulfurous-acid gas through a charge of pulp to agitate thesame mechanically and thereby assist in the leaching action, separatingthe solution from the ore, precipitating the metal from the solutionthereby releasing the gas and returning the sulfurous-acid gas releasedby the precipitating operation for use in agitating and dissolving metalfrom fresh charges of ore.

3. The hereindescribed improvement in leaching copper ores consisting insubjecting the ore-pulp to successive leaching operations in a series oftanks and forcing through the tanks in succession a gas containing thesolvent agent, beginning with that tank in which the ore is subjected tothe final leaching operation, as and for the purpose described.

4;. The herein-described improvement in treating ores in metallurgicaloperations consisting in subjecting the ore to successive operations ina series of tanks and forcing through the tanks in succession a gas containing the treating agent beginning with that tank in which the ore issubjected to the final operation and ending with that tank in which theore is subjected to the initial treatment, as and for the purposedescribed.

5. The herein-described improvement in treating ores, consisting inforcing sulfurousacid gas through a charge of pulp to agitate the samemechanically and to assist in the leaching action, then filtering thepulp to obtain the metal-bearing solution, precipitating the metal fromsuch solution thereby releasing the gas and returning the sulfurous-acidgas released by the precipitating process for use in agitating anddissolving metals from fresh charges of ore.

6. The herein-described improvement in treating copper or other ores,consisting in agitating a charge of pulp containing the ore by gas fromroasting-furnaces charged with material suitable for producingsulfurousacid gas, separating the resultant solution, precipitating themetal from the solution thereby releasing gas and employing thesulfurous-acid gas released by the precipitating process to enrich thegas derived from the furnace and used in leaching a charge of ore.

Signed at New York, in the county of New Signed at Salt Lake City, inthe county of York and State of New York, this 19th day Salt Lake andState of Utah, this 28th dayof of January, A. D. 1901. V January, AD.1901.

JAMES W. NEILL. J OAOHIM H. BURFEIND.

Witnesses: W'itneses:

DELBERT H. DECKER, J.'B. THOMPSON, E. L. LAWLER. r I FRANK GROCXER.

